Principles of Statistics – Data Collection & Questionnaire Design

Vocabulary flashcards summarizing essential terms and definitions from the lecture on data collection, survey methods, and questionnaire design in statistics.

Statistics

The science of collecting, organizing, analyzing, presenting, and interpreting data to aid decision-making and problem-solving.

Qualitative Data

Non-numeric information describing qualities or attributes, often gathered by observation and expressed with descriptive words (e.g., colour, gender, appearance).

Quantitative Data

Numeric, measurable information that expresses quantity, such as length, price, or duration.

Primary Data

Information collected firsthand for a specific research purpose.

Secondary Data

Information previously collected and often analyzed by someone else for a different purpose.

Published Secondary Data

Secondary data made available through government reports, books, journals, newspapers, or international organizations.

Unpublished Secondary Data

Secondary data found in diaries, letters, internal reports, or records held by individuals and organizations that are not publicly issued.

Reliability of Data

The degree to which data are dependable and free from error, assessed by examining source, method, timing, bias, and desired accuracy.

Suitability of Data

The extent to which existing data match the objectives, scope, and nature of a current study.

Adequacy of Data

Whether the precision and detail in existing data are sufficient for the researcher’s purpose.

Survey Data

Information obtained by observation or enquiry from existing units without researcher intervention.

Experimental Data

Information gathered after deliberately manipulating input variables and observing resulting changes in output.

Census

A complete enumeration that collects data from every unit in the target population.

Sample Survey

Data collection from a representative subset of the population to infer characteristics of the whole.

Cost Advantage (Sample Survey)

Lower expense of surveying a sample compared with a full census.

Speed Advantage (Sample Survey)

Faster data collection and summarization when only a sample is studied.

Accuracy Advantage (Sample Survey)

Potentially higher data quality because a smaller workload allows use of skilled personnel and closer supervision.

Questionnaire

A list of written questions (open or closed) completed by respondents themselves to provide data.

Schedule

A structured list of questions filled in by an interviewer on behalf of the respondent.

Direct Observation

Collecting data by watching subjects or events without interference.

Face-to-Face Interview

An interviewer personally asks questions and records responses in the presence of the respondent.

Telephone Interview

A data collection method using voice calls; rapid but limited for lengthy discussions.

Online Interview

Real-time data collection via internet platforms; limited to populations with digital access.

Sampling Unit

A clearly defined element or group of elements (e.g., household, person) considered for sample selection.

Sampling Frame

A list, map, or device that identifies all sampling units in the target population.

Sample Design

The plan specifying sample size, selection method, and procedures to meet survey objectives.

Target Population

The entire collection of elements about which a study seeks to draw conclusions.

Open-Ended Question

A survey item allowing respondents to answer in their own words, yielding rich qualitative data.

Closed-Ended Question

A survey item that offers respondents a predefined set of answer choices.

Multiple Choice Question

A closed-ended item presenting several mutually exclusive response options, often plus an 'other' category.

Rating Scale

A question format in which respondents indicate the degree of agreement or intensity (e.g., Likert scale).

Yes/No (Dichotomous) Question

A closed question permitting only two explicit choices, usually 'Yes' or 'No'.

Scaled Question

A survey item asking respondents to rate attitudes or opinions along an ordered continuum.

Matrix Question

A compact format that presents a set of similar scaled items in a grid for efficient response.

Pilot Survey (Pretest)

A small-scale trial of questionnaire and procedures to detect and correct design flaws before the main survey.

Covering Letter

A brief introduction sent with a questionnaire explaining purpose, assuring confidentiality, and encouraging response.

Field Worker

An individual trained to collect data in the field by observation or interviewing.

Questionnaire Design

The structured process of formulating, sequencing, and wording survey questions to obtain accurate data.

Leading Question

A survey question that suggests a desired answer and biases the respondent’s reply.

Ambiguous Question

A poorly worded survey item open to multiple interpretations, reducing comparability of responses.

Reference Period

The specific time span for which information is collected from each sampling unit.

Time Reference

The calendar period to which the survey results will relate (e.g., first quarter 2024).

Survey Process

Sequential stages of planning, designing, testing, conducting, and analyzing a survey.

Sampling Error

The difference between a sample estimate and the true population value arising from observing a subset rather than the whole population.

Non-Sampling Error

Errors in data collection or processing not related to the act of sampling, such as interviewer bias or data entry mistakes.

Questionnaire Pre-Testing

Evaluating a draft questionnaire with a small group to identify issues of clarity, flow, and length.

Tabulation Plan

The predetermined method for summarizing and presenting survey data, often using computer software.

Confidentiality Assurance

A promise to respondents that their individual data will not be disclosed, fostering honest answers.